Sony CD-R 80min-700Mb 40x (20) 20CDQ80NXSL User Manual

Both CD-R and CD-RW are outgrowths

of the original Sony/Philips CD

Red Book specification. CD-R is

defined by the Orange Book

Part II as well as the ISO

9660 CD-ROM CD/I stan-

dards. CD-RW conforms to

the Orange Book Part III.

Like conventional CD, both

types of discs have a reflective

layer. Like conventional CD, both

use a spiral track, with a track pitch

of 1.6 micrometers. Also like CD, the newer

discs both use laser playback, where the

alternation between bright and dark reflected light

equates to a digital 1. However, in order to record,

CD-R and CD-RW establish the course of the spiral

track with a pre-molded groove. And both CD-R and

CD-RW employ a recording layer, activated by

laser, to capture signals on the disc.

CD-R and CD-RW are very different in the way they

record signals. CD-R accomplishes recording by

burning permanent dark spots in the recording

layer. When the laser hits the substrate side of the

disc, its light is focused into the groove. The record-

ing layer’s organic dye absorbs the laser beam’s

energy, creating heat. This heat causes the plastic

substrate to deform and the dye to chemically

decompose. The result is a dark, non-reflective spot

on the disc.

By the way, the organic dye makes a difference

you can see with the naked eye. To enable record-

ing, CD-R discs must be visibly darker than CDs. Yet

CD-R media is light enough to be read on con-

ventional CD-ROM and DVD-ROM drives and

standard audio CD players.